I'm writing final exams for two intro chem courses. I try for a light touch brush of humor on at least a couple of the questions, it's stressful enough without every question probing deeply important things.
Some useful (in this context) unit conversions:
2000 mockingbirds = 2 kilomockingbirds
10-6 fish = 1 microfiche
454 graham crackers = 1 pound cake
10 millipedes = 1 centipede
10 monologs = 5 dialogues
2 monograms = 1 diagram
8 nickels = 2 paradigms
10-2 mental = 1 centimental
Have more to suggest?
A review of Freeman Dyson's "Dreams of Earth and Sky"
5 hours ago in The Curious Wavefunction